Magneto-electric ignition machine



Jan. 4 1927.

A. G. L. NEIGHBOUR IAGNETO ELECTRIC IGNITION MACHINE Patented Jan. 4, 1927.

UNITED STATES PATIENT OFFICE.

MAGNETO-ELECTRIG IGNITION MACHINE.

Application filed March 31, 1924, Serial No. 703,314, and in Australia April 6, 1928.

a fixed collecting element or elements if a distributor is not required. The high tension current at the instant of break or separation of the contacts of the prlmary interrupter or contact breaker, leaps across this small air gap and immediately preceding this instant the secondary winding is practically insulated from the remainder of the secondary circuit.

Experiment has shown that the rate of in- ,"ease of voltagein the secondary winding one of the main factors in the process of ignition and if said winding is insulated so that leakage currents cannot flow in various parts of the high tension circuit during the very short period in which the secondary voltage is rapidly increasing and immediately preceding the initiation of the spark, the rate of voltage rise will be much more rapid.

It is customary in high tension magnetos of the rotary armature type to connect the end of the secondary winding to an insulated slip ring on the armature shaft. The current is collected from this ring by a stationary collector or carbon brush; From the latter the current passes through a second conductor mounted in the interior of the distributer shaft to the rotary element of the distributer, which mayconsist of a rotating carbon brush, or if the distributer is of spark gap construction, of a rotating metal electrode.

It will, accordingly, be understood that high tension current passes from a rotating part, namely the slip ring, to stationary parts and again from the latter to a second rotating part, the distributer rotor, thereby making it necessary to employ two carbon brushes or like parts and several conductors. These parts and theirgmountings consider ably increase the complexity and cost of the machine. Moreover, the shp ring, collector brush, and said parts associated therewith,

and the cables and spark plugs, when a carbon brush distributer is used, provide leakage paths. in which currents flow during the very short period above mentioned, thereby decreasing the rate of increase of voltage in the secondary winding. Furthermore, owing to the wear of the carbon brushes, small particles of carbon vbecome deposited on the slip ring and other parts and these particles increase the leakage and require to be removed from time to time.

In this invention the high tension current passes directly from the rotatin armature to the rotor of the distributer, t ereby rendering the slip ring and collector brush un necessary, eliminating all stationary conductors, and considerably simplifying the construction and mounting of the distributer shaft.

A feature of theinvention resides in the provision of an insulated electrode or electrodes electrically connected with the secondary winding and rotating with the armature, and of a co-operating insulated, electrode or electrodes rotating with the distributer, the armature electrode and the eo-opcrating distributer electrodes being'arranged to move relatively to each other and being spaced apart a. short interval or distance, thereby forming a small air gap or succession of small air gaps across which the high tension currents leap when the machine is in operation. The insulated electrodes may be disposed concentrically about the armature and the distributer, and they may be, conveniently, arranged at the end of the armature at which the distributer pinion and gear wheel are located, and the front or rear of the magneto.

The armature may be provided with metallic electrodes and the distributer may be furnished with an insulated metal ring constructed as acontinuous ring electrode and concentrically disposed about its axis. The electrodes on the armature move closely past the co-operating ring electrode on the distributer and during the operation of the machine high tension currents spark across the small air gap situated therebetween. In some cases, continuous ring electrodes can be employed on both armature and distributer, or an axially disposed electrode can be used on the distributer and a plurality of concentrically arranged electrodes on the armature.

The invention, can be used in association winding P.

in associating the safety spark gap of the machine with the electrode or electrodes on the armature, thereby allording greater protection to the latter in the event of a breakdown occurring in the secondary circuit than is the case when the safety gap is located on the distributer or between the slip ring and the distributer.

A still further feature of the invention resides in the provision of means for pirculating air through and within the magneto to ensure eflicient removal of the products of ionization formed by the spark discharges across the small air gaps.

The invention is well adapted'for use in magnetos, wherein a timing sleeve having movable pole pieces mounted thereon and connected with the actuating cams of the interrupter, is employed to ensure uniformity of sparking in all positions of timing adjustments.

Reference being had to the drawings illustrating the invention F 'gure 1 is a view in longitudinal section of portion of a magneto illustrating one method of carrying out the invention.

Figure 2 is a view in transverse section on the line 2-2 in Figure 1.

Figure3 is a view in longitudinal section illustrating another method of carrying out the invention.

Figure 4 is a diagrammatical view illustrating the electrical circuits of the magneto shown in Figure 1.

Figure 5 is a View in transv'ersesection at the rear end of a magneto intended for use on a single-cylinder engine.

Figure 6 is a similar view to Figure 5 of a magneto for a twin-cylinder engine.

Figure 7 is a view in sectional plan on the line 77 in Figure 6.

In these drawings the numeral 10 designates the armature of a magneto having thereon a primary winding P, a secondary Winding S, and a condenser 0 associated in the usual way with an interrupter or contact breaker C connected with the primary Upon the armature 10 and conveniently mountedupon a shaft 11 thereof, is a sleeve or disk 12 of insulating material in which is fixed, preferably by moulding, one or more metal electrodes 13. l he electrodes 13 may be" separately constructed and connected by a conductor not shown), but they are, prefnuance erably, formed as radially extended portions of a metal ring 14 which is embedded in the sleeve 12 during manufacture.

The insulated or outer end of the secondary winding S, indicated by the numeral 15, is passed through a tube 16, or the like, of insulating material, and is connected to the metal ring 1 1 which with the electrodes 13 is thereby electrically associated with the secondary winding S.

Attention being directed more particularly to Figures 1, 2, and 4, of the drawings, a spur pinion 17 carried on the shaft 11 engages with a gear wheel 18 mounted on a shaft 19, hereinafter termed the distributer shaft, parallellydisposed to the armature 10.

Fixed to the gear wheel 18 and extending through transverse holes 20 therein, is a .block of insulating material 21 which for simplicity in manufacture may be constructed by moulding through and about the gear wheel 18.

The block of insulating material 21 has fixed therein, as by moulding, electrodes 22 which at certain times coact with the electrodes 13 to form spark gaps, and are hereinafter termed the co-operating electrodes. The co-operating electrodes-22 are likewise preferably formed as extensions of a metal ring 23 embedded in the block 21.

The electrodes 13 and the co-operating electrodes 22 are made of suliicient, circumferential length to provide for variations in the sparking period brought about by timing adjustments of the magneto.

In the block 21 is also iixed a distributing electrode 21 which is electrically connected with the ring 23 and co-operating electrodes 22 by a conductor 25.

The block 21 with the co-operating electrodes 22, ring 23, distributing electrode 24, and the conductor 25, comprise the rotating electrical elements of the distributor, and will be referred to hereinafter, as the distributer rotor.

One or both rings 14 and 23 may extend beyond the peripheries of the sleeve 12 and the block 21, respectively, and be constructed to have unbroken peripheral surfaces, thereby forming continuous ring electrodes as indicated by broken lines at 26 Figure 2. However, said rings are preferably constructed with electrodes 13 and 22 which extend radially -through and project beyond the'peripheries of the insulating sleeve 12 and block 21. In this manner the amount of exposed uninsulated metal surface is reduced to a minimum and leakagepf high tension currents is prevented as far as possible.

The distributing electrode 24 is adapted during its rotation to move without contact closelypast metal collecting segments 27 mounted in a block of insulating material .way through the primary winding P, as

shown in Figure 4.

The co-operating electrodes 22 and the ring 23 are connected to the remainder of vthe high tension circuit which comprises the conductor 25, distributing electrode 24,

collecting segments 27, and the terminals, cables, and spark plugs diagrammatically illustrated in Figure 4. p

The electrodes 13 on the armature 10 and the co-operating electrodes 22 "on the distributer rotor are rotated in opposite directions by the pinion 17 and gear wheel 18, and said electrodesare made of such radial lengths thatthey move closely past each other, but do not contact, being separated by a narrow s ace or air ap.

The electro cs 13 are is osed in such manner that one or other of t em ismoving past one of the co-operating electrodes 22 at each instant when an ignition spark is generated. synchronously the distributing electrode 24. is arran ed fto'pacs by one of the segments 27. A re ative position of these parts during an ignition period is shown in Figures 2 and 4. Accbrdingly when break or interruption of the primary circuit occurs,- an induced high tension secondary current will spark across the short air gap between an electrode 13 and-a co-operating electrode 22 and will pass through the conductor 25. and'over the air ga between the distributing electrode 24 an an adjoining segment i 27 and thence to the corresponding ignition lu p It will be obcerved that in the above described form, of the inyention, carbon brushes withtheir attendant disadvantages are entirely eliminated from the high tension circuit, and that all stationary conducting devices between. theend 15 of the secondary winding" S and the distributing electrode 24 are dispensed with.

Moreover the construction of the distributer is considerably simplified and the dis- ..tributer shaft19 can be-made solid and of [smaller diameter than the hollow shaft containing a high tensionayinsulated conductor commonly used on ma etos.- The shaft 19 can be mounted in i all bearings 29 as shown, and "said bearings can, be made smaller and accordingly cheaper than those ordinarily used with distributer shafts of hollow construction. I v M If preferred, a carbon brush distributer can be employed instead of the spark gap distributer described and illustrated.

The form of the invention above described has reference to the application thereof to a two-spark magneto in which two sparks are produced during each revolution of the armature, and in this case the electrodes 13 are two in number. Similarly by making the electrodes 13 to correspond in number to the sparks generated in each rev olution of the armature, the invention can 'be applied to a four-spark, a six-spark, or

other multi-spark magneto.

However, when the number of electrodes is considerably increased, the amount of exposed metal surface may exceed the insulated portions of the ring 14 to such an extent that it becomes moreexpedient to form the ing intended for application to a four-c lin-.

der engine. The magneto can also be a apted to engines having six or more c linders, and in such cases the number ofe ectrodes 22 and segments 27 'is made to correspond with the number of cylinders as will be readily understood 'When the number of electrodes 22 is considerably increased they can be formed as a continuous ring electrode in a similar manner to the electrodes 13 already described.

In Figure 3 is shown a form of the invention in which the distributer rotor is driven by bevel gearing, a bevel pinion 17 being mounted or'this purpose on the armature shaft 11. 4

The pinion 17 meshes with ,and. drives a bevel ear wheel 18", preferably formed integralf as by casting, with a hollow distributer shaft 19 In order to economize space as far as possible the shaft 19" may be inclined at an acute angle to the armature shaft 11, as illustrated in Figure 3.

The gearwheel 18 andthe shaft 19 can be supported on a single ball bearin 29 which is conveniently mounted in a' cup 30 fitting an inclined extension 31 of the cas in 31 of the magneto.

eans, as retaining nuts 32 and 33 can be used to respective y'secure the shaft 19 to the ball bearing 29" and to fiii said ball bearing in'the cup 30 which can beheld in position as by screws 34, one of which is shown in Figure 3.

Fitting'the interior of [the Shift 19 is'a block of [insulating material 21; which is maintained in fixed relationship to said shaft by means of one or more pins 35, or the like. The block 211 is made'a sliding lit in the shaft 19 and itcan be readily withdrawn therefrom without affecting the meshing of the'bevel pinion 1.7 with the gear wheel 18% The insulating block 21 is provided with. a conductor 25 which is furnished at its end adjoining the electrodes 13 with a co-operating electrode 2:2. The co-operating electrode "2" rotates upon its axis and is separated by a short interval from the path of the electrodes 13 with each of which it successively forms a spark gap as the armature revolves.

The opposite end of the conductor 25 is connected to a rotating distributing element or electrode 2% which as it rotates, passes by a series of collecting segments Q'P'mounted in an insulating block 28*.

The collecting segments 2? and the insulating block 28 form the distributor stator which as shown in Figure 3 is of flush type construction and is provided with sockets 36 into which the high tension cables are inserted and are fixed in the usual manner by pointed screws 37 passing through the segments 2?. I

In the form of the invention last described and illustrated in Figure 3, the number of parts is small and they are of simple construction and easily manufactured. Only one co-opereting electrode 22 is required on the distributor rotor irrespective of the number of sparks generated in each revolution of the armature 10 and the corresponding number of electrodes 13 thereon.

In this form of the invention the electrodes 13 can also be formed as a continuous ring electrode when the number of sparks generated in each revolution of the armature is sufficiently great.

The quantity of insulating material is considerably lessened and exposed metal. carrying high tension current is reduced to a small amount.

The distribute-r shaft 19 is mounted in a single ball bearing 29, thereby cheapening the cost of the machine, and the be vel pinion 17 and gear wheel 18 can be made considerably smaller and lighter for a given speed ratio than when spur gearing is employed. Accordingly, a further reduction in the weight and cost of the magneto is effected.

The electrodes 13 can be used to form one of the elements of the safety spark gap of electrodes 13 to prevent leakage of high tension currents by brush discharge or ionization.

Accordingly, an electrode 38 is fixed in the casing 31 and its inner end is situated at a required distance from the extremities of the electrodes 13 to form a safety gap therewith. The electrode 38 forms a saiet gap successively with each of the electro es 13 as the armature revolves and it is positioned in such manner that at each break one orother of the electrodes 13 will be adjacent. to it as clearly shown in Figures 2 and 4-.

In order that. the interior of the magneto may be effectively cooled and ventilated and to remove any products of ionization as ozone and nitric acid formed during the passage of the high tension currents across the air gaps, a fan 39 can be provided on the armature shaft 11.

The fan 39 is made of metal but'it can. if preferred, be formed by moulding blades (not shown) on the sleeve 12.

The fan 39 can induce a current of air through holes 40 made between the interrupter housin 41 and the interior of the magneto. Suitable induction openings 42 can be made in the cover 43 of the housin 41 to admit air and they can be provided with gauze or the like to exclude particles of dust or dirt.

The air drawn in by the fan 39 through the openings 4-2 and holes 40 is circulated within the magneto and is expelled through discharge orifices 44, preferably formed in the distributer stator. 1

In the construction shown in Figure 3, the air circulated by the fan 39, passes through holes 15 in the bearing cup 30 on its way to the discharge orifices 44.

The forms of the invention previously described relate to applications thereof to multi-spark magnetos in which distributors are used, but it can be used with advantage on magnetos which are intended for engines having one or two cylinders and in distributers are unnecessary.

For this purpose the end 15 of the secondary winding S is connected to a single insulated electrode 13 mounted on one end of the armature 10, as shown in Figures 5 and 6, and carried on an insulating block 12 fixed by screws 46 to the armature 10.

Fixed in the casing 31 of-the magneto is an insulated electrode 22 Figure 5 or a pair of insulated electrodes 22 Figure 6. These electrodes 22" are provided with suitable terminals as 47 which are connected by cables (not shown) with an engine on which the magneto is mounted.

As the electrode 13 rotates with the armawhich Oil ture it passes by the electrode or electrodes 22 without contact, being spaced therefrom stant when a spark is produced the electrode 13 is moving closely past-one or other of the electrodes 22* and at the moment of break a high tension current sparks across the air gap therebetween.

The electrode 13, in these forms of the invention can also function as one of the elements of the safety gap being provided with an extension 48 which coacts with an earthed electrode 38 which in these cases is fixed in the armature shaftll.

In these applications of the invention holes- 49 can be made in the casing 31 to ventilate the magneto and to permit the products of ionization to escape.

What I doclaim is 1. In a high tension magneto, an armature, a secondary winding on the armature, an insulated electrode in the secondary circuit, a grounded electrode, and an electrode on the armature connected to the secondary winding and forming with the insulated electrode a spark gap in the secondary circuit and with'the grounded electrode a safety a g In a high tension magneto, an armature, a secondary winding on the armature, an insulated electrode in' the secondary cir-r cuit, a grounded electrode, and electrodes on the armature connected with the secondary -winding and forming alternately a spark gap in the secondary circuit with the insulated electrode and a safety gap with the grounded electrode.

3. In a hightension magneto, an armature, a secondary winding onthe armature,

an insulated electrode in the secondary circuit, a grounded electrode, and oppositely disposed electrodes on the armature connected to the secondary winding and alternately forming a spark gap in the secondary circuit with the insulated electrode and a safety gap with the gio'unded electrode.

insulated electrode in the secondary circuit co-operating in succession with the electrodes on the armature to form a spark gap in said circuit.

6. In a high tension magneto, an armature, a secondary winding on the armature, an electrode mounted on and rotating with the armature and connected with thes'econdary windin a distributer, and an in- '65 ing with the distributer and co-operating to form a spark gap in succession with the electrodes on the armature.

8. In a high tension magneto, an armature, a secondary winding on the armature, oppositely disposed electrodes mounted on and rotating with the armature and connected to the secondary winding, a distributer, and an insulated electrode mounted on and rotating with the distributer and co-operating alternately with the electrodeson the armature to form a spark gap in the secondary circuit;

9. In a high tension magneto, an armature, a secondary winding on the armature,

an electrode mounted on the armature and connected to the secondary winding, a dis'-' tributer having a rotor and a stator, an insulated electrode on the rotor co-operating with the electrode on the armature to form a spark gap in the secondary circuit, a distributing element on the rotor, collecting segments on the stator, and a conductor on the rotor connecting the insulated electrode with the distributing element.

10. In a high tension magneto, an armature, a secondary winding on the armature, a plurality 'of electrodes mounted on and rotating with the armature and connected to the secondary winding, a distributer having a' rotor and a stator, an insulated electrode on the rotor co-operatmg in succession wlth the electrodes on the armature to form a spark gap in the secondary circuit, a distributing element on the-rotor, collecting segments on the stator, and a conductor on the rotor connecting the insulated electrode with the distributing element. i

11. In a high tension magneto, an armature, a secondary winding on the armature, an electrode mounted on the armature and connected to the secondary winding, a distributer inclined to the armature, and an insulated electrode on the distributer co-operating to form a spark gap with the electrode on the armature. 12'. In a high tension magneto, an armature, a secondary winding on the armature, a plurality of electrodes mounted on and rotating with the armature and connected to the secondary winding, a distributer angu larly inclined to the armature, and an In sulated electrode on' the axis of the distributer co-operating to form a spark gap in succession with the electrodes on the armature,

13: In a high tension magneto, an armature, a secondary winding thereon, 0ppositely disposed electrodes mounted on and rotating with the armature and connected to the secondary winding, a distributer angularly inclined to the armature and having a rotor and a stator, an insulated electrode on one end of the rotor co-operating alternately with the electrodes on the armature to form a spark gap in the secondary circuit. a distributing element on the opposite end of the rotor, collecting segments on the stator, and an axial conductor on the rotor connecting the insulated electrode with the distributing element,

14-. In. a high tension magneto, an armature, a secondary winding on the armature, an armature shaft, a hollow distributor shaft, bevel gearing operatively connecting said shafts, an insulating sleeve on the armature shaft, a metal ring embedded in the insulating sleeve and connected to the secondary winding, electrodes on the metal ring, an insulating block fitting the hollow distributor shaft, and an electrode .on the insulating block co-operating alternately with the electrodes on said ring to form a spark gap in the secondary circuit.

15- In a high tension magneto, an armature, a secondary winding thereon, electrodes mounted on and rotating with the armature and connected to the secondary winding, a

distributor angularly inclined to the armature, a bevel pinion on the armature shaft, a bevel gear on the distributor engaging the bevel ,inion, a hollow distributer shaft integrall y formed with the bevel gear, an insulating block detachably and non-turnably fitting the hollow distributor shaft, an axially disposed electrode on the inner end of the insulating block cooperating to form a spark gap in succession with the electrodes on the armature, a distributing element on the opposite end of said block, an axial con ductor in the block connecting the axially disposed electrode with the distributing element, and collecting segments coacting with the distributing element.

16. In a high tension magneto in combination with the mechanism set forth in claim 15,a bearing cup supporting the distributor and detachably fitting an inclined extension of the magneto casing, a ball bearing fixed in the bearin cup and rotatively supporting the hollow distributer shaft, and means for securing said shaft in the ball bearing.

17. In a high tension magneto, an armature, a secondary winding thereon, electrodes mounted on and rotating with the armature and-connected to the secondary winding, a distributer, an insulated electrode on the distributer co-operating in succession with ture, a secon the electrodes on the armature to form a spark gap in the secondary circuit, a distributing electrode electrically associatedelectrode mounted on the armature and connected to the secondary winding and forming a spark gap in the secondary circuit with the insulated electrode and a safety gap with the grounded electrode.

19. In a high tension magneto, an armature, a secondary winding thereon, a distributer, an insulated electrode rotating with the distributor, a grounded electrode, and a plurality of electrodes mounted on and rotating with the armature and connected to the secondary winding and forming in succession a spark gap in the secondary circuit with they insulated electrode and a safety gap with the grounded electrode.

20. In a high tension magneto, an armature, a secondary windin thereon, a distributer angularly incline to the armature, an insulated electrode mounted on and rotating with the distributer, a grounded electrode, and oppositely disposed electrodes mounted on and rotating with the armature and connected with the secondary winding and forming alternately a spark gap in the secondary circuit with the insulated electrode and a safety gap with the grounded electrode.

21. In a highten'sion magneto, an armature, a secondary winding on the armature,.

ture, a secondary winding on the armature,

an electrode mounted on thearmature and connected to the secondary winding, a distributor, an insulated electrode on the distributor co-operating to form a spark gap in the secondary circuit with theelectrode on the armature, an air circulating fan on the armature shaft, and induction and discharge openings. i

23. In a hi h tension magneto, an armadary winding thereon, a plurality of electrodesmounted on and rotating with the armature and connected to the sec- ,ondary winding, a distributer having a rotor and a stator, an insulated electrode on the rotor co-operating to form spark gaps with the electrodes on the armature, a distributing element on the rotor electrically associated with the insulated electrode, collectors on the stator, spark gaps between the the cover, passages between the interrupter distributin element and the collectors, and housing and the mterior of the magneto and an air circu ating fan on the armature shaft. between the latter and the distributer, and 10 24. In a high tension magneto in combinadischarge openings in the distributer stator. 6 tion with the mechanism set iorth'in claim In testimony w ereof I aflix-my signature.

23, an interrupter housing, a cover on the v I terrupter housing, induction openings in ARTHUR GEORGEILOYD NEIGIIIOUR. 

